No Fact Check at AP?

On July 16, the Associated Press moved this story (linked here to yesterday's Clarion Ledger) which reported:

Democrat Ronnie Musgrove has filed a complaint with the Federal Elections Commission accusing U.S. Sen. Roger Wicker of accepting illegal campaign contributions...Musgrove filed his complaint Wednesday.

On July 18, the Associated Press moved this story which reports:

The Federal Elections Commission says it has not yet seen a complaint filed by Democrat Ronnie Musgrove's campaign against U.S. Sen. Roger Wicker.

I wonder, can you file a complaint without the person you're filing with know it? Did the AP report this based on a Musgrove Campaign press release? Where is the fact check?